Barium Hydroxide Lime
»Barium Hydroxide Lime is a mixture of barium hydroxide octahydrate and Calcium Hydroxide.It may contain also Potassium Hydroxide and may contain an indicator that is inert toward anesthetic gases such as Ether,Cyclopropane,and Nitrous Oxide and that changes color when the Barium Hydroxide Lime no longer can absorb carbon dioxide.
Caution—Since Barium Hydroxide Lime contains a soluble form of barium,it is toxic if swallowed.
Packaging and storage— Preserve in tight containers.
Labeling— If an indicator has been added,the name and color change of such indicator are stated on the container label.The container label indicates also the mesh size in terms of standard-mesh sieve sizes (see Powder Fineness á811ñ).
Identification—
A: Place a granule of it on a piece of moistened red litmus paper:the paper turns blue immediately.
B: A1in 10solution of it in 6Nacetic acid responds to the tests for Barium á191ñand for Calcium á191ñ,and it may respond also to the flame test for Potassium á191ñ.
Particle size á786ñ Screen 100g for 5minutes as directed under Method I,using a mechanical shaker.It passes completely through a No.2standard-mesh sieve,and not more than 2.0%passes through a No.40standard-mesh sieve.Not more than 7.0%is retained on the coarse-mesh sieve,and not more than 15.0%passes through the fine-mesh sieve designated on the label.
Loss on drying á731ñ Weigh accurately,in a tared weighing bottle,about 10g,and dry at 105for 2hours:it loses between 11.0%and 16.0%of its weight.
Hardness— Screen 200g on a mechanical sieve shaker (see Particle Size Distribution Estimation by Analytical Sieving á786ñ)having a frequency of oscillation of 285±3cycles per minute,for 3minutes,to remove granules coarser than 4-mesh and finer than 8-mesh.Weigh 50g of the granules retained on the screen,and place them in a hardness pan of the following description:the hardness pan has a diameter of 200mm and a concave brass bottom,and the bottom of the pan is 7.9mm thick at the circumference and 3.2mm thick at the center and has an inside spherical radius of curvature of 109cm.Add 15steel balls of 7.9-mm diameter,and shake on a mechanical sieve shaker for 30minutes.Remove the steel balls,brush the contents of the hardness pan onto a sieve of the fine-mesh size designated on the label,shake for 3minutes on the mechanical sieve shaker,and weigh:the percentage of Barium Hydroxide Lime retained on the screen is not less than 75.0,and represents the hardness.
Carbon dioxide absorbency— Fill the lower transverse section of a U-shaped drying tube of about 15-mm internal diameter and 15-cm height with loosely packed glass wool.Place in one arm of the tube about 5g of anhydrous calcium chloride,and accurately weigh the tube and the contents.Into the other arm of the tube place 9.5g to 10.5g of Barium Hydroxide Lime,and again weigh accurately.Insert stoppers in the open arms of the U-tube,and connect the side tube of the arm filled with Barium Hydroxide Lime to a calcium chloride drying tube,which in turn is connected to a suitable source of supply of carbon dioxide.Pass the carbon dioxide through the U-tube at a rate of 75mLper minute for 20minutes,accurately timed.Disconnect the U-tube,cool to room temperature,remove the stoppers,and weigh:the increase in weight is not less than 19.0%of the weight of Barium Hydroxide Lime used for the test.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(RMI)Radiopharmaceuticals and Medical Imaging Agents
USP28–NF23Page 219
Phone Number:1-301-816-8305